WASHINGTON (Reuters) - President Barack Obama appears ready to gamble in the debate over gun control.

By signaling on Monday that he will ask Congress to ban military-style assault weapons, Obama is embarking on a high-risk strategy that is likely to further inflame tensions with Republicans at a time when feelings already are raw because of a series of running budget battles.

At a White House news conference, Obama said he favored a "meaningful" assault weapons ban, stronger background checks for gun buyers and tighter controls on high-capacity magazine clips in the wake of the Newtown, Connecticut, school massacre last month that brought the national debate over guns to the forefront.

The Democratic president essentially is betting that any blowback from an assault-weapons plan would not doom other proposals that some Republicans may find more palatable.

At the very least, Obama's plan could make life more difficult for gun-friendly Democrats who are less enthusiastic about an assault-weapons ban.

Obama will need their backing to pass the package of gun-control measures he plans to introduce this week after the Newtown shooting that killed 20 children and six adults.

During the news conference, Obama acknowledged that he is not likely to get everything he wants.

"Will all of them get through this Congress? I don't know," Obama said. "But what's uppermost in my mind is making sure that I'm honest with the American people and with members of Congress about what I think will work."

Obama's aggressive approach is likely to cheer gun-control advocates, who say that an assault-weapons ban could limit the scope of future attacks like the one in Newtown.

But some observers said that given the emotional nature of the gun-control debate, Obama risks an overreach that could threaten other measures that enjoy broader political support.

"If he tries to go too big on gun control, the narrative is going to turn too quickly against him," said John Hudak, a fellow at the nonpartisan Brookings Institution.

"If he pursues an assault weapons ban, it will fail and undermine his ability to get anything through Congress," Hudak added.

A HEAVY LIFT

Obama is expected to reveal the details of his plan later this week after weighing proposals assembled by Vice President Joe Biden.

A White House aide said the three ideas outlined by Obama on Monday would be the "bare minimum" of any proposal.

Democratic Representative Bobby Scott of Virginia, who along with several other lawmakers met with Biden earlier on Monday, said he was not sure what Obama ultimately would recommend.

"That is going to be the president's call," Scott said in a telephone interview with Reuters. "Everyone knows that a ban on assault weapons would be a legislative challenge."

Public sentiment shifted in favor of increased gun-control measures after the December 14 shootings in Newtown but an assault-rifle ban is less popular than other proposals.

A Pew Research Center pool showed 85 percent of Americans favor broadening background checks to private and gun-show sales and 55 percent back an assault-rifle ban. Other polls show similar results.

The National Rifle Association and other gun-rights groups fiercely oppose banning assault rifles, which are popular with the gun-buying public.

Republicans who control the House of Representatives are expected to oppose a ban and several members of the Democrat-led Senate who represent gun-friendly rural states also are leery of the idea.

"It's hard to define what an assault weapon is and if we're just defining it by what it looks like, that doesn't do much for me," Senator Angus King of Maine, an independent who caucuses with Democrats, said on "CBS This Morning."

Other proposals appear to stand a greater chance of legislative success. Republicans could accept expanded background checks depending on the details, a Republican aide in the Senate said.

Biden told gun-control advocates this month that expanding the background-check system to cover private sales and gun shows would be the single most effective way to reduce gun violence, said Vincent DeMarco, national coordinator of Faiths United to Prevent Gun Violence.

Obama also can take steps on his own to address gun violence.

He could strengthen the database used to check the background of prospective gun buyers by directing federal agencies to provide more information to the FBI, which handles the program. He also could order the Justice Department to place a greater priority on prosecuting people who lie on their gun background checks.

But Obama could anger members of Congress if he acts before they do.

One newly elected Republican warned Obama on Monday that the president could risk impeachment if he used his executive power to tighten gun controls.

"If the president is allowed to suspend constitutional rights on his own personal whims, our free republic has effectively ceased to exist," Representative Steve Stockman of Texas said in a statement.

Gun-control advocates say that public anger could work in their favor as well. After years in which gun-rights advocates dominated the debate in Washington, they say the Newtown incident has shifted the discussion.

"People's feelings are so raw on this and they're going to stay raw for a long time," DeMarco said. "They want something to happen and they want something substantial."

(Additional reporting by Jeff Mason and Thomas Ferraro; Editing by David Lindsey and Bill Trott)